Steps:

1. Lay out all soap-making utensils. Line the mold with freezer paper.

2. Measure out any herbs or additives and place nearby.

3. Wearing goggles, a surgical mask and gloves, dissolve the lye in a pitcher of ice and water and stir.

4. Weigh out hard fats into a stainless steel pot. Place the pot on the stove and melt the fats.

5. Once the hard fats are melted, put the pot back on the scale and measure in the oils. Mix.

6. Pour off 16 ounces of oil into a separate bowl. Mix cocoa powder into this bowl and blend well; set aside.

7. When the lye solution and the pot of oils are both near 110 degrees Fahrenheit, stir the lye solution into the pot. Blend with an immersion blender; alternate with power on and power off, stirring as if with a spoon.

8. Stir until the soap mixture reaches the "trace" stage, like thin to medium pudding.

9. Stir in additives, fragrance or essential oils.

10. Pour into the mold.

11. To achieve a marbled look, drizzle the mixture of cocoa powder and oils into the soap in the mold, and drag a craft stick through the soap, evenly dispersing the chocolate throughout the mold in a marbling pattern.

12. Set the mold aside in a box and cover with another box.

13. When soap shows signs of cooling by becoming opaque at the edges, put a heavy towel over the whole mold to keep it warm.